It is well known that as the expansion ratio, as compared to charge density of an internal combustion engine is increased, more energy is extracted from the combustion gases and converted to kinetic energy, increasing the thermodynamic efficiency of the engine. It is further understood that increasing air charge density increases both power and fuel economy due to further thermodynamic improvements. The objectives for an efficient engine are to provide a high-density charge, to begin combustion at maximum density and then to expand the gases as far as possible against a piston, vane or rotor lobe.
It is further known that if the air-fuel charge of an engine is homogeneous, the elimination of cycle-to-cycle variations in components, (pressures, air-fuel ratios, temperatures, etc.), will greatly improve engine performance.
It is also well known that if an air-fuel mixture has a high air content, and because fuel is fully mixed with air before combustion, the fuel bums cooler bringing the bum temperature below the threshold at which it would damage the pistons.
It is also an established principle that the lower the temperature of a standard density charge is at the time of ignition, the lower the comparative peak temperature and pressure produced which further reduces polluting emissions, especially NOX.
Now, the compression ratio of current engine technology sets the level to which a piston “compacts” a mix of air and fuel before the charge is ignited and hence sets the limits of power and efficiency. If the ratio is too high in gasoline or gas engines, the fuel ignites itself as it does in a Diesel engine. Although efficiency is high with a Diesel engine, polluting emissions, including particulates (smoke and nano-particles, all caused by pre-mixed fuel-bum) make it a health hazard.
The engine of this invention is capable of producing the same “compactness” of charge and an even denser charge than that of the Diesel engine, but without having a high compression ratio or producing excessively high temperature. The charge is introduced and managed in such a manner that regardless of the charge density, the temperature of the charge can be kept below auto-ignition temperature of the fuel until the point for ignition. The homogeneous charge then bums cooler and more completely for truly clean power production.
Described herein is a unique engine, which, within its combustion chambers, produces a lighter than normal or denser than normal, temperature-adjusted homogeneous air-fuel mixture. The temperature of the charge is so managed that at 10-15 degrees before piston top dead center (TDC), the charge can be very low and optionally below auto-ignition temperature, and it is at that point that the charge is ignited by spark, heat infusion or heat profusion or by catalyst for high torque, power and efficiency with ultra low polluting emissions.